A099097 → basis A013610

nonnegative coefficients

Proved for all n: all roots real, in (−∞, 0] · coefficients of one sign · Hadamard kernel what this means

Recurrence
\(P_{n}(x) = \left(1 + 3\,x\right)\,P_{n-2}(x) + \left(3 + 9\,x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 1\)
\(P_{2}(x) = 3 + 9\,x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
23912
3105781148
4332797837291824
5109122151129477656122480
63605022279457751710716359049277056
7118919854137808508869105413411612975314413414592
8392776365635121292823180819371335163512223143478296942083328
9129702878592790018154230755318063111711603716084947612595151743046721518658304
1042837106845311825001762129813152161988675712361588870809186695223312770527233874204896392232960
111414813917661487446753588570811731015279571631742013086951138205091939252105462953812784876137348678440178781428736
124672801422327619652333416269613028966614707345413096019489929471118594370667725462454336123206487291112668649990331381059609970946076672
131543321512174527780771447154685018443500823611952328244236258055739401471694819769251994920148930637642737332510484768720124478203115728242953648111966478635008
145097243183167361303438166230683280654211289910858104629036824038330353651411051797621557721617556645780328667741375943592821388839326740149571269121444700686832541865828329147481527926784
15168350506512246851168338073512884819337097583339587553687633739482212722345679269400358474589166449489538329303781944103002415287386493444412350610046661281111531977422117773116712577228767924549611817644249661440

Computed in your browser ?

Technical details
Node id
n-a34da8080d75981c · revision 1 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-96b8deba61407ebd

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, intercept -1)
  • Palindromic rows: no
  • γ-positive (gamma_positive): no
  • Nonnegative coefficients (nonn): yes
  • Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): no

OEIS matches ?

No OEIS matches.

OEIS submission text ?

Fields to paste into an OEIS submission: the example %e, the formula %F and programs %t (Mathematica) and %o (PARI/GP) that list the same rows. For an OEIS link the row numbers, the offset and the orientation are those of the entry, as matched; the matched terms were compared with the published ones, which identifies the node with the entry on a finite prefix, not for every n. The PARI/GP program is not machine-checked here.

The atlas's own rows: n = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:     1;
   2:     3,       9;
   3:    10,      57,       81;
   4:    33,     279,      783,      729;
   5:   109,    1221,     5112,     9477,      6561;
   6:   360,    5022,    27945,    77517,    107163,     59049;
   7:  1189,   19854,   137808,   508869,   1054134,   1161297,     531441;
   8:  3927,   76365,   635121,  2928231,   8081937,  13351635,   12223143,    4782969;
   9: 12970,  287859,  2790018, 15423075,  53180631, 117116037,  160849476,  125951517,   43046721;
  10: 42837, 1068453, 11825001, 76212981, 315216198, 867571236, 1588870809, 1866952233, 1277052723, 387420489;
%F Formula
The row polynomials satisfy P(n,x) = (1+3*x)*P(n-2,x) + (3+9*x)*P(n-1,x) for n >= 3, with P(1,x) = 1, P(2,x) = 3 + 9*x.
%t Mathematica
P[1, x_] := 1;
P[2, x_] := 3 + 9*x;
P[n_, x_] := P[n, x] = Expand[(1 + 3*x)*P[n - 2, x] + (3 + 9*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; v[2] = 3 + 9*x; for(n = 3, N, my(i = n); v[i] = (1 + 3*x)*v[i - 2] + (3 + 9*x)*v[i - 1]); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

Generated with polytool c48629374597.

Proved properties

  • Real-rooted. Every row P_n, n >= 1, is zero or real-rooted with all roots in (-inf, 0]
    Every polynomial of the sequence has only real roots, inside the stated interval.
    by the cited steps: e-c6fadefda20cf4de
  • Coefficients of one sign. Every nonzero row, n >= 1: the coefficients of P_n have one sign
    All coefficients of each polynomial have the same sign (after x -> -x when alternating).
    derived from the cited steps by a stated theorem: e-c6fadefda20cf4de
  • Hadamard kernel (Malo). Rows P_n, n >= 1, are Hadamard kernels (preserve real-rootedness)
    Multiplying the coefficients of any real-rooted polynomial termwise by those of a row (Hadamard product) gives a real-rooted polynomial again.
    derived from the cited steps by a stated theorem: e-c6fadefda20cf4de

Proof chains

1 incoming proof step. Each step is expanded back to the roots of the proof DAG, the theorem checks of a node's own rule. JSON

No candidate equalities or related sequences.

References

  1. [MW08] Shi-Mei Ma and Yi Wang. q-Eulerian polynomials and polynomials with only real zeros. The Electronic Journal of Combinatorics, 15(1):Research Paper 17, January 2008. doi:10.37236/741